Thinking differently - the energy hierarchy
The three Rs of the European waste minimisation hierarchy - reduce, reuse, recycle - can be applied across sustainable development, particularly to energy.
The first, most cost beneficial, thing to do is to reduce the amount of what is needed.
Reduction means reducing the amount of energy needed by the occupants of buildings while still maintaining or improving comfort conditions. Much can be achieved through passive design. Energy use can also be reduced through careful planning of our towns and cities. Locating community facilities, retail and jobs close to homes will help reduce the need for car journeys. Reducing energy use is a priority for both existing and new buildings.
When all easily achievable methods of reduction are in place it’s time to think about how to take a waste product and redirect it to replace an input - reuse.
Reuse involves the provision of efficient energy supply systems such as combined heat and power installations. These reuse the waste heat as a resource to replace the need for prime energy fuels to make heat separately. Thermal masterplanning allows the careful planning and location of uses to ensure ‘waste’ heat from one user can be re-used in another building.
Existing resources can also be reused to prevent energy being used to process additional raw materials. This can include reusing water within buildings, for example for toilets and garden irrigation, to avoid the high energy costs in treating potable water or reusing materials for new development.
Once all practical reuse methods are in place, you should consider taking an output that needs some processing applied to it before it replaces an input - recycling.
Recycling means the provision of renewable energy to meet the energy demand after we have reduced the need for energy and applied efficiency in supply. It can also include extracting energy from waste and using products that contain recycled materials.
In general terms, £1 spent on energy reduction will save more CO2 than £1 spent on energy reuse, which will save more CO2 than £1 spent on recycling. These principles apply at all scales of implementation and should directly inform strategic frameworks for energy delivery at the sub-regional and city scales.
However, it is important to avoid going for easy wins at the cost of longer term, more strategic options. A long-term strategy based on the energy hierarchy should help inform the delivery of energy infrastructure. The energy hierarchy underpins thinking on the Merton Rule and has been used as a principle for planning policy in statutory documents such as the Cornwall Structure Plan. The energy hierarchy has also been translated and used in the form of the “Lean, Clean and Green” mantra in the London Plan.
CABE and Urban Practitioners
with the cities of Birmingham, Bristol, Leeds, Liverpool, Manchester, Newcastle, Nottingham and Sheffield